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Publication Citation: Persistence of Singly Dispersed Silver Nanoparticles in Natural Freshwaters, Synthetic Seawater, and Simulated Estuarine Waters

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Author(s): Stephanie L. Chinnapongse; Robert I. MacCuspie; Vincent A. Hackley;
Title: Persistence of Singly Dispersed Silver Nanoparticles in Natural Freshwaters, Synthetic Seawater, and Simulated Estuarine Waters
Published: April 28, 2011
Abstract: The use of silver nanoparticles (AgNPs) in consumer products has become increasingly widespread over the past decade. These products are being used and distributed world-wide, creating a risk of AgNPs flowing into rivers and oceans via wastewater. Though AgNPs are desirable for their antimicrobial properties, their dissolution to more soluble Ag(I) species in aqueous media has raised concerns about human and environmental safety. Recent literature on AgNP behavior is limited on the colloidal stability under environmentally relevant conditions, indicating that many of these effects have not been quantitatively studied and leaves the question unanswered of whether AgNPs themselves pose novel toxicity risks. This paper focuses on the persistence and colloidal stability of AgNPs in natural freshwaters and lab-prepared synthetic waters to assesses the potential risk AgNPs may have on aquatic environments. Ultraviolet-visible spectroscopy, dynamic light scattering, and atomic force microscopy were used to evaluate the colloidal stability of the AgNPs in locally-obtained pond water, moderately hard reconstituted water alone or with natural organic matter, synthetic seawater, and also the individual chemicals most prevalent in seawater. Singly dispersed AgNPs in seawater and samples with greater than 20 mmol,L-1 sodium chloride were unstable, with the absorbance approaching zero within the first ten hours of mixing. Other samples, mostly those with lower salinity, maintained varying degrees of colloidal stability during time studies up to 48 h. This indicated greater availability of AgNPs in freshwater, and also likelihood that some AgNPs will be stable long enough in freshwater to successfully enter estuarine or marine systems. While these studies show that AgNPs have a definite potential to affect both fresh and saltwater systems, many steps are left to be taken to obtain a thorough risk assessment of AgNPs in the environment. The results of this work should enable
Citation: Science of the Total Environment
Volume: 409
Issue: 12
Pages: pp. 2443 - 2450
Keywords: Silver nanoparticle persistence, colloidal stability, nanoparticle dispersions, environmental fate of silver nanoparticles
Research Areas: Nanotech/Environment, Health & Safety
PDF version: PDF Document Click here to retrieve PDF version of paper (735KB)